Wiring questions '76 911

[Jesse911]

So guys i'm working on the electrics in my 76 911. I think sometime in the past the wiring has been changed to a 77 because the car still had the mechanical speedo (cut off) but now an electronic speedo with all wiring looking original. This could have been done when they changed the engine to a 77 Carrera 3 from a sportomatic car.

Therefore I'm a bit lost with the wiring and also not everything was connected/working when I bought the car.


So these wires, I guess the white green one is for a rear fog light? But the white black and black wire?





What is connected to this blue wire? This is coming from the connector to the ventilation control panel.




These wires are all coming from the wiper regulator. So I have a blue wire in the connector, a double red and brown. Brown could be added to the wiper motor ground. But the rest?



The yellow wire above with black sleve does this go to this wire?






If anyone could help me that would be great! Thanks

[E Sully]

Gn/Wh is rear fog light. Bk is clock, glove compartment light, interior lights. Bk/Wh front trunk light.

Blue wire is for optional Webasto heater.

[Nditiz1]

They went to electronic speedos in 76 if you have a mechanical in there it is not the correct one unless they put an early trans in.

[Jesse911]

Originally Posted by Nditiz1

They went to electronic speedos in 76 if you have a mechanical in there it is not the correct one unless they put an early trans in.

Maybe it is an early '76 car because I also have the hand throttle. The gearbox is '78 manual coupled to a '77 Carrera 3.0 engine from a sportomatic. So a bit of mix and match . The speedo is an electronic one from a later turbo. But the wiring in the tunnel all looks OEM. That's why I think they might swapped the harness.

Originally Posted by E Sully

Gn/Wh is rear fog light. Bk is clock, glove compartment light, interior lights. Bk/Wh front trunk light.

Blue wire is for optional Webasto heater.

Thanks for this information.

If anyone else can comment on the red, brown yellow and blue wire with the connector coming from the wiper regulator I would be very happy.

[E Sully]

It's difficult with cars that have been altered with no real history.
Wiper motor wiring can depend on if it has intermittent wipers. Here is a bit of what I found if it was equipped with them.

[timmy2]

Originally Posted by E Sully

Gn/Wh is rear fog light. Bk is clock, glove compartment light, interior lights. Bk/Wh front trunk light.

Blue wire is for optional Webasto heater.

In the harness branch he is asking about,
Black is stage 1 rear defogger, white/black is stage 2 rear defogger, green/white is rear fog lamp.

Blue is for optional Webasto heater.

Yellow in the location pictured, is for the starter solenoid and does need to be connected.

Work your way through the wiper controls according to what has been posted.

[E Sully]

I can't argue with Dennis, he knows wire harnesses better than me. I gave a look into some old photo's of my 73.5. Cig lighter on the left, defrost on the right.
In the previous photo you can see the Black wire I thought it was in the upper left connected to the light bulb.

[Jesse911]

Thanks guys for the help. I start to understand the current flow diagrams a little bit better and the wipers are working!

3 speeds on the stalk. The intermittent button works (stalk in off position) but it doesn't matter how much I dial the knob the interval does not change. Any ideas?


Next problem .

I have this green/white/black wire coming for the harness to the hazard relay. I checked the diagram and I can't seem to find this wire. I do find it between the relay and stalk and this one is connected as it should however this extra wire I can't find where it goes.

The problem is that at the moment the indicators do not work. However if I press in the hazard light button and put the stalk in left or right position all indicators start blinking.

[IROC]

Originally Posted by Nditiz1

They went to electronic speedos in 76 if you have a mechanical in there it is not the correct one unless they put an early trans in.

Early '76 cars had a mechanical speedo. Mine does and it was built in December 1975.

[E Sully]

There are 3 Gn/W/Bk. One goes from the turn signal stalk to the emergency flasher switch 49a. Then from the emrgency flasher switch to the flasher unit 49a. From the flasher unit it then jumps to the indicator light in the oil gauge.

[Jesse911]

Thanks Ed! That was the thing I was looking for.

Working on the indicators.

See attached photo. Originally the blue wires were taped off and only the black green and black white were attached to the light bulbs for the indicators in the gauge. Together with 2 not original ground wires. According to the diagram the blue wires should be connected together with the black green or white wires and no ground wire.




It seems that the problems has something to do with this. Depending on if I only connect the blue wires or only the black/green/white wires my indicators work.

Can anybody help me how this should be connected?

[timmy2]

The photo is correct for the turn signal indicators.
Has anyone done any mods to the flasher relay wiring?
Or incorrect 4 pole flasher relay installed?

[Jesse911]

Originally Posted by timmy2

The photo is correct for the turn signal indicators.
Has anyone done any mods to the flasher relay wiring?
Or incorrect 4 pole flasher relay installed?

You mean the wiring is correct if I take out the not original ground wires?

I bought a new relay but I will double check if it is the correct one. The old one had a cracked housing.

No mods as far as I can see it all looks original.

[E Sully]

Here is the back of my tachometer with the wiring.



The Bl/W jumps to the left and right indicator bulbs. The Bk/Gn goes to the left indicator, Bk/W to right indicator. Grounding is through the flasher relay, not the brown wire on the gauge.
Bk/Bl on the far sides of the gauge are instrument back lighting bulbs. It travels from the light switch to all the gauges. W/Bl wire bottom lamp bottom is high beam indicator. Terminal strip wires Bk/Pl is tach signal, the R/Bk is gauge power, and Brown is gauge ground, jumps to all gauges.
I believe you should remove the double tab piece from the back of the bulbs.



In this thread is a description of how the emergency flasher, turn signals work.
http://forums.pelicanparts.com/porsche-911-technical-forum/1154724-71-turn-signal-function.html

[timmy2]

The double tabs are why I asked if any mods were done.
They shouldn’t be there.
Also the blue white normally goes to the center terminal and the black/white or green go to the bulb case terminal.

[Jesse911]

Thank you both very much!

I removed the double tab pieces and non original brown/yellow ground wires. Also ordered some new original bulb holders as the ones in the car do not seem to be the correct ones. Will receive them tomorrow and try.

I will let you know.

[E Sully]

You should only have one Bn/Y wire. That is from the parking brake to the Brake warning light in the oil gauge.

[Jesse911]

It all works guys thanks!

Only thing is that when the parking brake is on the light flashes quite rapidly in the oil gauge and also the indicator lights in the tacho light up. Is this correct?

[E Sully]

I've been looking into this a bit. What type of flasher relay do you have. I believe original is NLA, 914-618-303-11, Hella 71373 TBB44 4DB 003425-02. Later superceded ones may not work the same, but I'm not sure yet.
https://www.early911sregistry.org/forums/showthread.php?171471-1972-911-Flasher-Unit

[Jesse911]

Originally Posted by E Sully

I've been looking into this a bit. What type of flasher relay do you have. I believe original is NLA, 914-618-303-11, Hella 71373 TBB44 4DB 003425-02. Later superceded ones may not work the same, but I'm not sure yet.
https://www.early911sregistry.org/forums/showthread.php?171471-1972-911-Flasher-Unit

That is the one I have. Came in a Porsche box. Maybe my parts supplier had these still in stock.